Metabolically diverse primordial microbial communities in Earth’s oldest seafloor-hydrothermal jasper
Papineau, D.; She, Z.; Dodd, M.S.; Iacoviello, F.; Slack, J.F.; Hauri, E.; Shearing, P.; Little, C.T.S. (2022). Metabolically diverse primordial microbial communities in Earth’s oldest seafloor-hydrothermal jasper. Science Advances 8(15): eabm2296. https://dx.doi.org/10.1126/sciadv.abm2296
In: Science Advances. AAAS: New York. ISSN 2375-2548; e-ISSN 2375-2548, more
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| Authors | | Top |
- Papineau, D.
- She, Z.
- Dodd, M.S.
- Iacoviello, F.
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- Slack, J.F.
- Hauri, E.
- Shearing, P.
- Little, C.T.S.
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| Abstract |
The oldest putative fossils occur as hematite filaments and tubes in jasper-carbonate banded iron formations from the 4280- to 3750-Ma Nuvvuagittuq Supracrustal Belt, Québec. If biological in origin, these filaments might have affinities with modern descendants; however, if abiotic, they could indicate complex prebiotic forms on early Earth. Here, we report images of centimeter-size, autochthonous hematite filaments that are pectinate-branching, parallel-aligned, undulated, and containing Fe2+-oxides. These microstructures are considered microfossils because of their mineral associations and resemblance to younger microfossils, modern Fe-bacteria from hydrothermal environments, and the experimental products of heated Fe-oxidizing bacteria. Additional clusters of irregular hematite ellipsoids could reflect abiotic processes of silicification, producing similar structures and thus yielding an uncertain origin. Millimeter-sized chalcopyrite grains within the jasper-carbonate rocks have 34S- and 33S-enrichments consistent with microbial S-disproportionation and an O2-poor atmosphere. Collectively, the observations suggest a diverse microbial ecosystem on the primordial Earth that may be common on other planetary bodies, including Mars. |
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